what does the orifice do for my car

What Does The Orifice Tube Do For My A/C?

It is good to be a little technically educated in order to know how to run a house, electronic gadget, or an automobile. Right now, you are trying to learn more about the air conditioning system of your car. If you want to find out more about the ins and outs of the orifice tube, you have come to the right place. Here is all the information you need in order to understand what an orifice tube is.

What Is The Orifice Tube?

The orifice tube is that copper tube you see with two screens on either side. Orifice tubes are sometimes confused with the expansion valves. The latter is in a way the predecessor of the former. Their functions are pretty much the same. The orifice tube has replaced the valve in most of the new models. Unlike the valve system, the orifice tube itself has no part that can move to open or shut. It has the same function as the valve, but with a different mechanism.


The orifice tube regulates flow of refrigerant into the car. This is the component at work when you turn the air conditioner high or low. You key in the demand with some buttons and knobs you turn to regulate the flow of cool air. The orifice tube takes this information and controls the activity of the compressor, and sometimes, the refrigerant flow into the compressor, to give you exactly that amount of cooling that you asked for. The orifice tube also acts as a separator between the high-pressure section and the low pressure section in the air conditioning setup.


There is a brass hole that meters the required amount of refrigerant liquid and lets the required amount pass from the high pressure side to the low pressure side. This lets the temperature of the refrigerant go lower as the high pressure to low pressure movement happens, much like in an aerosol spray can. The cool liquid with a low pressure flows into the next part that is the evaporator.

The valve inside the compressor regulates the flow of refrigerant into it before it enters the process of going through the heating cooling cycle. With this system, the cooling happens much faster than with the valve system. Also, since there are no smaller movable parts like the moderating rod, in the orifice as there are in the expansion valve, the chances of the vent tube getting clogged or a part breaking off are nil.

Importance Of The Orifice Tube

Controlling the amount of refrigerant flow into the evaporator is important. If an uncontrolled amount of refrigerant entered through the evaporator, it could freeze the traces of atmospheric moisture on the evaporator coil, thereby creating crystals that block the air flow. Without an orifice tube, the air conditioning system would not be working.

Even if the compressor, condenser, evaporator, and all the major components are functioning right and the refrigerant is cooling as it should, without the orifice tube, the interior of the car will not receive the cool fresh air and the entire system will eventually begin to get damaged.